U.S. patent application number 11/572699 was filed with the patent office on 2008-01-24 for radiation-curable resin composition for shape-replication, sheet for shape-replication, and shape-replicated material.
This patent application is currently assigned to Dainipoon Ink and Chemicals Inc.. Invention is credited to Nobuo Kobayashi, Hidetoshi Konno, Masatoshi Motomura, Kenji Shoumura, Hiroyuki Terada, Hiroyuki Tokuda.
Application Number | 20080021174 11/572699 |
Document ID | / |
Family ID | 35786256 |
Filed Date | 2008-01-24 |
United States Patent
Application |
20080021174 |
Kind Code |
A1 |
Tokuda; Hiroyuki ; et
al. |
January 24, 2008 |
Radiation-Curable Resin Composition for Shape-Replication, Sheet
for Shape-Replication, and Shape-Replicated Material
Abstract
A radiation-curable resin composition for shape-replication of
the present invention includes a polyester resin (R) whose number
average molecular weight (Mn) is 1,000 to 8,000; and a
polymerizable vinyl compound (V), wherein a temperature (T4), at
which a complex viscosity (.eta.*) of components excluding any
solvent at a frequency of 1 Hz is 1.times.10.sup.4 dPas, is
30.degree. C. or higher, and a temperature (T6), at which a complex
viscosity (.eta.*) at a frequency of 1 Hz is 1.times.10.sup.6 dPas,
is 100.degree. C. or lower.
Inventors: |
Tokuda; Hiroyuki;
(Sakura-shi, JP) ; Kobayashi; Nobuo; (Chiba-shi,
JP) ; Motomura; Masatoshi; (Ichihara-shi, JP)
; Terada; Hiroyuki; (Ichikawa-shi, JP) ; Shoumura;
Kenji; (Sakura-shi, JP) ; Konno; Hidetoshi;
(Mobara-shi, JP) |
Correspondence
Address: |
DARBY & DARBY P.C.
P.O. BOX 770
Church Street Station
New York
NY
10008-0770
US
|
Assignee: |
Dainipoon Ink and Chemicals
Inc.
Tokyo
JP
|
Family ID: |
35786256 |
Appl. No.: |
11/572699 |
Filed: |
July 27, 2005 |
PCT Filed: |
July 27, 2005 |
PCT NO: |
PCT/JP05/13720 |
371 Date: |
January 25, 2007 |
Current U.S.
Class: |
525/397 ;
525/451 |
Current CPC
Class: |
C08G 63/52 20130101;
C08F 283/01 20130101 |
Class at
Publication: |
525/397 ;
525/451 |
International
Class: |
C08G 63/12 20060101
C08G063/12; C08G 63/195 20060101 C08G063/195; C08G 63/88 20060101
C08G063/88 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 29, 2004 |
JP |
2004/221688 |
Claims
1. A radiation-curable resin composition for shape-replication
comprising: a polyester resin (R) whose number average molecular
weight (Mn) is 1,000 to 8,000; and a polymerizable vinyl compound
(V), wherein a temperature (T4), at which a complex viscosity
(.eta.*) of components excluding any solvent at a frequency of 1 Hz
is 1.times.10.sup.4 dPas, is 30.degree. C. or higher, and a
temperature (T6), at which a complex viscosity (.eta.*) at a
frequency of 1 Hz is 1.times.10.sup.6 dPas, is 100.degree. C. or
lower.
2. A radiation-curable resin composition for shape-replication
according to claim 1, wherein a temperature (T5), at which the
complex viscosity (.eta.*) at a frequency of 1 Hz is
1.times.10.sup.5 dPas, is 40.degree. C. to 80.degree. C., and the
temperature difference (T4-T6) between the temperature (T4) and the
temperature (T6) is 20.degree. C. or higher.
3. A radiation-curable resin composition for shape-replication
according to claim 2, wherein the polyester resin (R) contains an
unsaturated double bond.
4. A radiation-curable resin composition for shape-replication
according to claim 3, wherein the polyester resin (R) is obtained
by using a polycarboxylic acid component and a polyol component as
essential raw materials, and a maleic acid and/or fumaric acid are
used as a part or all of the polycarboxylic acid component.
5. A radiation-curable resin composition for shape-replication
according to claim 3, wherein the polyester resin (R) is obtained
by using a polycarboxylic acid component and a polyol component as
essential raw materials, and bisphenols and/or their alkylene oxide
adducts are used as a part or all of the polycarboxylic acid
component.
6. A radiation-curable resin composition for shape-replication
according to claim 1, wherein the polymerizable vinyl compound (V)
is a (meth)acrylic compound containing 2 to 6 unsaturated double
bonds.
7. A radiation-curable resin composition for shape-replication
according to claim 1, wherein the polyester resin (R) has a number
average molecular weight (Mn) of 1,500 to 5,000.
8. A radiation-curable resin composition for shape-replication
according to claim 7, wherein the polymerizable vinyl compound (V)
is a (meth)acrylic compound containing 2 to 6 unsaturated double
bonds.
9. A radiation-curable resin composition for shape-replication
according to claim 1, wherein a weight ratio (R/V) of the polyester
resin (R) and the polymerizable vinyl compound (V) is 40/60 to
90/10.
10. A radiation-curable resin composition for shape-replication
according to claim 1, further comprising a polyether-modified
and/or polyester-modified silicone compounds.
11. A radiation-curable resin composition for shape-replication
according to claim 10, wherein the content of the
polyether-modified and/or polyester-modified silicone compounds in
the components excluding any solvent is 1 to 15 wt %.
12. A radiation-curable resin composition for shape-replication
according to claim 11, wherein the polyether-modified and/or
polyester-modified silicone compounds (S) is a silicone compound
containing a (meth)acryloyl group.
13. A radiation-curable resin composition for shape-replication
according to claim 1, further comprising a photoinitiator.
14. A radiation-curable resin composition for shape-replication
according to claim 1, wherein the temperature (T4) is 55.degree. C.
or higher, and the temperature (T6) is 60.degree. C. or lower.
15. A sheet for shape-replication, wherein a radiation-curable
resin composition for shape-replication according to claim 1 is
laminated on one side or both sides of a sheet-type resin
substrate.
16. A sheet for shape-replication according to claim 15, wherein
the sheet-type resin substrate comprises a poly(ethylene
terephthalate) resin.
17. A shape-replicated material produced by shape-replicating a
sheet for shape-replication according to claim 15 and curing the
sheet-with irradiation.
Description
CROSS REFERENCE TO PRIOR APPLICATION
[0001] This is a U.S. national phase application under 35 U.S.C.
.sctn.371 of International Patent Application No. PCT/JP2005/013720
filed Jul. 27, 2005, and claims the benefit of Japanese Application
No. 2004-221688 filed Jul. 29, 2004, both of them are incorporated
by reference herein. The International Application was published in
Japanese on Feb. 2, 2006 as International Publication No. WO
2006/011506 under PCT Article 21(2).
TECHNICAL FIELD
[0002] The present invention relates to a radiation-curable resin
composition for shape-replication which can be preferably used for
the production of a shape-replicated material such as an optical
lens, a projection screen, or an embossed sheet for building and
decorative material. Also, the present invention relates to a sheet
for shape-replication and a shape-replicated material made from the
above sheet.
BACKGROUND ART
[0003] Known examples of a production method of an optical sheet
used for an optical lens, a projection screen, and the like include
an injection molding process, an extrusion molding process and a
press molding process. However, in these production methods, there
were problems in that it was difficult to mold a sheet to a large
size and that numerous molds were needed for mass production.
[0004] Therefore, a production method is known which uses a
radiation-curable resin composition such as an ultraviolet-curable
resin and a mold such as a cylindrical mold for a lens so as to
continuously form a lens on one or both sides of a sheet-type
substrate. As a resin composition used in this production method, a
radiation-curable resin composition has been proposed, which
includes a thermoplastic polymer, a monomer containing one or more
unsaturated double bonds in a molecule, and a photoinitiator (for
example, see Japanese Unexamined Patent Application, First
Publication No. Hei 7-128503 (pages 2 to 5) ("JP '503").
[0005] However, in the radiation-curable resin compositions
disclosed in "JP '503", one kind of an acrylic resin such as
poly(ethyl methacrylate) is used as a thermoplastic polymer in
order to obtain a shape-replicated material such as an optical lens
with a favorable mechanical property. As a result, in the case of
dissolving the composition in a solvent to make a uniform solution,
flow-casting this solution on the sheet-type substrate, and then
removing the solvent by evaporation to laminate the composition on
the sheet-type substrate, there is a problem that it is easy to
foam due to vaporized solvent so that it is difficult to obtain a
uniform coating film.
[0006] Even if the forming due to vaporized solvent could be
preventable during the lamination on the sheet-type substrate, the
aforementioned radiation-curable resin composition has a high
viscosity during shape-replicating by using a cylindrical mold.
Moreover, even when the composition is heated so as to
shape-replicate it at a high temperature, in the temperature range
in which a sheet-type resin substrate is not deformed due to heat,
the viscosity reduction is small in the radiation-curable resin
composition produced by using an acrylic resin such as poly(ethyl
methacrylate) as a thermoplastic polymer. Therefore, it is
difficult to realize an improvement in the shape-replicating
property, and the shape on the cylindrical shape cannot be
precisely replicated.
[0007] When an acrylic resin with a low molecular weight is used as
a thermoplastic polymer in order to prevent these problems, it
becomes easy to prevent foaming, and the viscosity reduction due to
heating is appropriately increased. Therefore, it is possible to
obtain a radiation-curable resin composition with an excellent
shape-replicating property. However, there are problems in that the
resulting cured material becomes brittle and that the cured
material has a poor mechanical property. Then, it is difficult to
obtain a radiation-curable resin composition with a favorable
balance of a shape-replicating property and a mechanical property
of a cured material.
[0008] Also, known examples of a production method of a resin
complex which is suitable as a protective film or a coating
material include a production method of a resin complex including a
first irradiation step of irradiating a shape-replicated material
of a radiation-curable composition with radiation, in which a
radiation-polymerizable compound (A) and a chain polymer (B) are
uniformly mixed, so as to change the shape-replicated material into
a semi-cured material in transparent and solid states, without flow
ability; and the second irradiation step of further irradiating the
semi-cured material with radiation at a temperature which is higher
than during the irradiation in the first irradiation step and
higher than a glass transition temperature of the semi-cured
material (for example, see Japanese Unexamined Patent Application,
First Publication No. 2002-200623 (pages 2 and 17) ("JP '623").
[0009] As an example of a radiation-curable composition which is
preferably used in the case of obtaining a shape-replicated
material, "JP '623" discloses a composition including a
polyester-based polymer as a chain polymer (B). Specifically,
Examples of "JP '623" disclose a radiation-curable resin
composition including a polyarylate-based polymer as a chain
polymer (B). However, a radiation-curable composition, which is
described to be preferable in "JP '623", has problems in that it is
difficult to mix a radiation-polymerizable compound (A) and a chain
polymer (B) and that a shape-replicating property is not
sufficient. Because of poor solubility to solvents, there is a
problem that it is necessary to use a solvent with strong
solubility and a strong influence on the human body and
environment, for example a halogenated hydrocarbon such as
methylene chloride.
SUMMARY OF THE INVENTION
[0010] Therefore, an object to be achieved by the present invention
is to provide a radiation-curable resin composition for sheet for
shape-replication with excellent balance of a shape-replicating
property and a mechanical property of a cured material; a sheet for
shape-replication in which this radiation-curable resin composition
for shape-replication is laminated on one side or both sides of a
sheet-type resin substrate; and a shape-replicated material
produced by shape-replicating the above sheet and then curing it
with irradiation.
[0011] The present inventors have intensively researched a solution
to the above objects, and found:
[0012] (1) In a radiation-curable resin which is described to be
preferable in ("JP '623"), polyarylate used as a chain polymer (B)
has a large number average molecular weight of about 16,000, which
is one of the reasons the shape-replicating property and solubility
to solvents are not sufficient.
[0013] (2) As for a radiation-curable resin composition including a
polyester resin and a polymerizable vinyl compound, wherein a
temperature, at which a complex viscosity (.eta.*) of the
components excluding any solvent at a frequency of 1 Hz is
1.times.10.sup.4 dPas, is 30.degree. C. or higher, the thickness
change of the resin layer, which is made of this radiation-curable
resin composition for shape-replication laminated on a sheet-type
resin substrate, due to the flow hardly occurs before
shape-replicating step.
[0014] (3) As for a radiation-curable resin composition including a
polyester resin and a polymerizable vinyl compound wherein a
temperature, at which a complex viscosity (.eta.*) at a frequency
of 1 Hz is 1.times.10.sup.6 dPas, is 100.degree. C. or lower, when
this radiation-curable resin composition for shape-replication is
laminated by heating and melting on a sheet-type resin substrate,
this heating requires relatively lower temperature, for example
40.degree. C. to 110.degree. C. At this heating temperature, a
polymerizable vinyl compound in the composition is hardly gelated
and can be laminated uniformly.
[0015] (4) By using a polyester resin whose number average
molecular weight is 1,000 to 8,000, it is possible to easily obtain
a radiation-curable resin composition with the aforementioned
characteristics (2) and (3), i.e. a resin composition wherein a
temperature, at which a complex viscosity (.eta.*) of the
composition excluding any solvent components at a frequency of 1 Hz
is 1.times.10.sup.4 dPas, is 30.degree. C. or higher, and a
temperature, at which a complex viscosity (.eta.*) at a frequency
of 1 Hz is 1.times.10.sup.6 dPas, is 100.degree. C. or lower.
[0016] (5) A mechanical property is excellent in a
radiation-curable resin composition including a polyester resin (R)
whose number average molecular weight (Mn) is 1,000 to 8,000; and a
polymerizable vinyl compound (V), a temperature (T4), at which a
complex viscosity (.eta.*) of the components excluding any solvent
at a frequency of 1 Hz is 1.times.10.sup.4 dPas, is 30.degree. C.
or higher, and a temperature (T6), at which a complex viscosity
(.eta.*) at a frequency of 1 Hz is 1.times.10.sup.6 dPas, is
100.degree. C. or lower.
[0017] In addition, there is the case where the composition can be
flow-cast on a sheet-type resin substrate by appropriately heating
it even without any solvent. In the case of preparing a solution
using a solvent, it is possible to dissolve the composition without
using a solvent with strong solubility. Since the above case
requires a small amount of a solvent, foams hardly occur while
removing the solvent by evaporation after the solution has been
flow-cast on a sheet-type resin substrate. Also, since the
viscosity reduction due to heating within the temperature range, in
which a sheet-type resin substrate does not come under the
influence of deformation by heating, is appropriately large, it is
easy to improve a shape-replicating property (i.e. characteristics
of precisely replicating even a fine shape of a mold and keeping
the shape) due to heating, and balance of a shape-replicating
property and a mechanical property of a cured material is
favorable.
[0018] The present invention was completed on the basis of the
aforementioned knowledge.
[0019] In other words, the present invention provides a
radiation-curable resin composition for shape-replication including
a polyester resin (R) whose number average molecular weight (Mn) is
1,000 to 8,000; and a polymerizable vinyl compound (V), wherein a
temperature (T4), at which a complex viscosity (.eta.*) of
components excluding any solvent at a frequency of 1 Hz is
1.times.10.sup.4 dPas, is 30.degree. C. or higher, and a
temperature (T6), at which a complex viscosity (.eta.*) at a
frequency of 1 Hz is 1.times.10.sup.6 dPas, is 100.degree. C. or
lower.
[0020] Also, the present invention provides a sheet for
shape-replication wherein this radiation-curable resin composition
for shape-replication is laminated on one side or both sides of a
sheet-type resin substrate; and a shape-replicated material
produced by shape-replicating the above sheet and curing it with
irradiation.
[0021] In the present specification, "acrylic acid" and
"methacrylic acid" are collectively referred to as "(meth)acrylic
acid", and "acrylate" and "methacrylate" are collectively referred
to as "(meth)acrylate".
[0022] A radiation-curable resin composition for shape-replication
of the present invention is excellent in a mechanical property of a
cured material. In addition, there is the case where it is possible
to flow-cast the composition on a sheet-type resin substrate by
appropriately heating it without any solvent. In the case of
preparing a solution using a solvent, it is possible to dissolve
the composition without using a solvent with a strong solubility.
Also, since the above case requires a small amount of solvent,
foams hardly occur while removing the solvent by evaporation after
the solution has been flow-cast on a sheet-shape-replicated resin
material. In addition, it is easy to improve a shape-replicating
property by heating, and the balance of a shape-replicating
property and a mechanical property of a cured material is
favorable. Also, it is easy to obtain a cured material which is
excellent in a mechanical property and on which a shape of a mold
such as a lens pattern is precisely replicated.
[0023] Hereinafter, the present invention is described in
detail.
[0024] In a polyester resin (R) used in the present invention, it
is essential that a number average molecular weight (Mn) is 1,000
to 8,000. In particular, a number average molecular weight (Mn) is
preferably 1,500 to 5,000 because the viscosity reduction due to
heating within the temperature range, in which a sheet-type resin
substrate does not come under the influence of deformation by
heating, for example 30.degree. C. to 100.degree. C., is
appropriately large, it is possible to obtain a radiation-curable
resin composition for shape-replication in which the balance of a
shape-replicating property and a mechanical property of a cured
material is more favorable, and solubility to solvents is
favorable. Furthermore, in a polyester resin (R) used in the
present invention, a softening point is preferably 80.degree. C. to
150.degree. C. on the basis of a ball and ring method.
[0025] A polyester resin whose number average molecular weight (Mn)
is lower than 1,000 is not preferable because a mechanical property
of a cured material becomes deteriorated so that the cured material
becomes brittle. Also, a polyester resin whose number average
molecular weight (Mn) is higher than 8,000 is not preferable
because this polyester resin is difficult to be mixed with other
components such as an unsaturated double bond-containing monomer
(M), and a shape-replicating property becomes deteriorated. Also, a
polyester resin whose number average molecular weight (Mn) is lower
than 1,000 or higher than 8,000 is not preferable because it is
difficult to control the components of radiation-curable resin
composition excluding any solvent to have a temperature (T4) of
30.degree. C. or higher at which a complex viscosity (.eta.*) at a
frequency of 1 Hz is 1.times.10.sup.4 dPas and a temperature (T6)
of 100.degree. C. or lower at which a complex viscosity (.eta.*) at
a frequency of 1 Hz is 1.times.10.sup.6 dPas.
[0026] It is preferable that the aforementioned polyester resin (R)
contain an unsaturated double bond because a sufficient crosslink
density can be obtained after curing on the exposure to radiation.
Also, the branched polyester resin (R) can be used.
[0027] Examples of the aforementioned polyester resin (R) include a
resin obtained by using a polycarboxylic acid component and a
polyol component as essential raw materials.
[0028] There is no particular limitation to the aforementioned
polycarboxylic acid component, and examples thereof include a
dicarboxylic acid or an anhydride thereof such as succinic acid,
adipic acid, sebacic acid, azelaic acid, dodecenyl succinic acid,
n-dodecyl succinic acid, malonic acid, maleic acid, fumaric acid,
citraconic acid, itaconic acid, glutaconic acid,
cyclohexanedicarboxylic acid, orthophthalic acid, isophthalic acid,
or terephthalic acid; and a carboxylic acid containing tri- or
polyfunctional groups or an anhydride thereof such as trimellitic
acid, trimethinic acid, or pyromellitic acid. In addition, lower
alkyl carboxylates can be used as a polycarboxylic acid component.
Herein, the lower alkyl group means an alkyl group containing 1 or
more and 4 or less carbon atoms. These polycarboxylic acid
components can be used alone or in a combination of two or more.
Among them, it is more preferable that maleic acid and/or fumaric
acid be used as a part or all of polycarboxylic acid components
because an unsaturated double bond can be introduced in the
resulting polyester resin, and it is possible to obtain a polyester
resin excellent in solubility with a polymerizable vinyl compound
(V). In addition, a monocarboxylic acid such as benzoic acid,
p-toluic acid, p-tert-butyl benzoic acid can be used together
according to need.
[0029] There is no particular limitation to the aforementioned
polyol component, and examples thereof include a divalent alcohol
such as an ethylene glycol, triethylene glycol, 1,2-propylene
glycol, 1,3-propylene glycol, 1,4-butanediol, 1,3-butanediol,
1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, hydrogenated
bisphenol A, or bisphenols-alkylene oxide adducts; tri- or
polyvalent alcohols such as a glycerine, trimethylolethane,
trimethylolpropane, trishydroxyethyl isocyanurate, or
pentaerythritol. These polyol components can be used alone or in a
combination of two or more. Among them, it is more preferable that
bisphenols and/or their alkylene oxide adducts be used as a part or
all of polyol components because it is easy to obtain a
radiation-curable resin composition in which the components
excluding any solvent are easily controlled to have a temperature
(T4) of 30.degree. C. or higher at which a complex viscosity
(.eta.*) at a frequency of 1 Hz is 1.times.10.sup.4 dPas and a
temperature (T6) of 100.degree. C. or lower at which a complex
viscosity (.eta.*) at a frequency of 1 Hz is 1.times.10.sup.6
dPas.
[0030] Therefore, it is particularly preferable that the polyester
resin (R) be obtained by using maleic acid and/or fumaric acid as a
part or all of polycarboxylic acid components and bisphenols and/or
their alkylene oxide adducts as a part or all of polyol components.
Herein, when a polyester resin is produced by using the
polycarboxylic acid components and the polyol components, an
esterification catalyst such as dibutyltin oxide can be used
appropriately.
[0031] There is no particular limitation to a polymerizable vinyl
compound (V) used in the present invention, and examples thereof
include any kinds of a polymerizable vinyl monomer and a
polymerizable vinyl oligomer, for example a (meth)acrylic monomer
such as .beta.-hydroxyethyl(meth)acrylate,
.beta.-hydroxypropyl(meth)acrylate, glycidyl(meth)acrylate,
.beta.-hydroxyethyl(meth)acryloyl phosphate,
dimethylaminoethyl(meth)acrylate, diethylaminoethyl(meth)acrylate,
ethylene glycol di(meth)acrylate, diethylene glycol
di(meth)acrylate, triethylene glycol di(meth)acrylate, polyethylene
glycol di(meth)acrylate, propylene glycol di(meth)acrylate,
dipropylene glycol di(meth)acrylate, tripropylene glycol
di(meth)acrylate, polypropylene glycol di(meth)acrylate,
trimethylolpropane di(meth)acrylate, trimethylolpropane
tri(meth)acrylate, pentaerythritol tri(meth)acrylate,
pentaerythritol tetra(meth)acrylate, dipentaerythritol
tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate,
dipentaerythritol hexa(meth)acrylate, or
tris[2-(meth)acryloyloxyethyl]isocyanurate; or a (meth)acrylic
oligomer such as polyester(meth)acrylate, bisphenol-type
epoxy(meth)acrylate, novolak-type epoxy(meth)acrylate, or
urethane(meth)acrylate. Each of these polymerizable vinyl monomer
and polymerizable vinyl oligomer can be used alone, while it is
usually preferable to use a polymerizable vinyl monomer alone or to
use polymerizable vinyl monomers together with polymerizable vinyl
oligomers. Among them, it is particularly preferable to use
polymerizable vinyl monomers together with polymerizable vinyl
oligomers. In addition, it is preferable that a polymerizable vinyl
oligomer have a number average molecular weight which is more than
200 and less than 2,000, and less than a number average molecular
weight (Mn) of a polyester resin (R).
[0032] In these polymerizable vinyl compounds (V), because a
sufficient crosslink density can be obtained after curing on
exposure to radiation, it is preferable to use the following
(meth)acrylic compounds containing 2 to 6 unsaturated double bonds
in a molecule as an essential component: ethylene glycol
di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene
glycol di(meth)acrylate, propylene glycol di(meth)acrylate,
dipropylene glycol di(meth)acrylate, tripropylene glycol
di(meth)acrylate, trimethylolpropane di(meth)acrylate,
trimethylolpropane tri(meth)acrylate, pentaerythritol
tri(meth)acrylate, pentaerythritol tetra(meth)acrylate,
dipentaerythritol tetra(meth)acrylate, dipentaerythritol
penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and
tris[2-(meth)acryloyloxyethyl]isocyanurate.
[0033] A radiation-curable resin composition for shape-replication
of the present invention is required to include the aforementioned
polyester resin (R); and the aforementioned polymerizable vinyl
compound (V), wherein a temperature (T4), at which a complex
viscosity (.eta.*) of the components excluding any solvent at a
frequency of 1 Hz is 1.times.10.sup.4 dPas, is 30.degree. C. or
higher, and a temperature (T6), at which a complex viscosity
(.eta.*) at a frequency of 1 Hz is 1.times.10.sup.6 dPas, is
100.degree. C. or lower. When the aforementioned temperature (T4)
is lower than 30.degree. C., the thickness change of the resin
layer, which is made of radiation-curable resin composition for
shape-replication laminated on a sheet-type resin substrate, due to
the flow easily occurs before a shape-replicating step; therefore,
this composition is not preferable. When the aforementioned
temperature (T6) is higher than 100.degree. C., it is required to
increase a heating temperature when the radiation-curable resin
composition for shape-replication is laminated by heating and
melting on a sheet-type resin substrate. As a result, a
polymerizable vinyl compound in the radiation-curable resin
composition for shape-replication is gelated, and so it becomes
difficult to be uniformly laminated. In addition, it is required to
increase a heating temperature when the radiation-curable resin
composition for shape-replication is shape-replicated. As a result,
there is a possibility of a problem occurring in that thermal
deformation occurs in a sheet-type resin substrate such as
poly(ethylene terephthalate) whose softening point is low;
therefore, this composition is not preferable.
[0034] In a radiation-curable resin composition for
shape-replication in the present invention, the temperature (T4) is
preferably 40.degree. C. or higher and more preferably 55.degree.
C. or higher. Also, the temperature (T6) is preferably 80.degree.
C. or lower and more preferably 60.degree. C. or lower. Among them,
a radiation-curable resin composition for shape-replication having
the temperature (T4) of 40.degree. C. or higher and the temperature
(T6) of 80.degree. C. or lower is preferable, and a
radiation-curable resin composition for shape-replication having
the temperature (T4) of 55.degree. C. or higher and the temperature
(T6) of 60.degree. C. or lower is more preferable.
[0035] Examples of a radiation-curable resin composition for
shape-replication of the present invention include a composition
including the aforementioned polyester resin (R) and the
aforementioned polymerizable vinyl compound (V) as essential
components and further including a resin other than the polyester
resin (R), a photoinitiator, other additives, a solvent, and so on
according to need.
[0036] In the case where the viscosity change of a
radiation-curable resin composition for shape-replication is too
sensitive for the temperature, a small change of temperature during
a shape-replicating step has an unignorable influence on a
shape-replicating property. Therefore, it is preferable that a
radiation-curable resin composition for shape-replication of the
present invention have appropriate temperature sensitivity.
Specifically, the temperature difference (T4-T6) between the
temperature (T4) and the temperature (T6) is preferably 20.degree.
C. or higher and more preferably 20.degree. C. to 50.degree. C. In
this case, a temperature (T5), at which the complex viscosities
(.eta.*) at a frequency of 1 Hz are 1.times.10.sup.5 dPas, is
preferably 30.degree. C. to 100.degree. C. and more preferably
40.degree. C. to 80.degree. C.
[0037] The polyester resin (R) and the polymerizable vinyl compound
(V) can be mixed in any ratio as long as the temperature (T4), at
which a complex viscosity (.eta.*) of the components of
radiation-curable resin composition for shape-replication excluding
any solvent to be obtained at a frequency of 1 Hz is
1.times.10.sup.4 dPas, is 30.degree. C. or higher, and a
temperature (T6), at which a complex viscosity (.eta.*) at a
frequency of 1 Hz is 1.times.10.sup.6 dPas, is 100.degree. C. or
lower. In particular, the weight ratio (R/V) is preferably within a
range of 40/60 to 90/10 because it is easy to obtain a
radiation-curable resin composition for shape-replication in which
the temperature difference (the temperature (T4)-the temperature
(T6)) is 20.degree. C. or higher, and the temperature (T5) is
30.degree. C. to 100.degree. C. Also, a combination of the
polyester resin (R) and the polymerizable vinyl compound (V) can be
selected arbitrarily, but the combination in which a composition
can have transparency is preferable in the case where the use of a
resulting shape-replicated material is optical articles.
[0038] In the present invention, a complex viscosity (.eta.*) of
the components excluding any solvent in a radiation-curable resin
composition for shape-replication at a frequency of 1 Hz is
1.times.10.sup.4 dPas is obtained by measuring it using rheometer
RS500 produced by HAAKE Co., Ltd. under the conditions of a
measurement frequency: 6.28 rad/sec. (1 Hz), a measurement starting
temperature: 25.degree. C., a measurement completion temperature:
150.degree. C., a rate of temperature increase: 2.degree. C./min.
Also, the temperatures (T4), (T5), and (T6) can be obtained by the
charts of the measurement results of temperature changes of the
complex viscosities (.eta.*).
[0039] As described above, a radiation-curable resin composition
for shape-replication of the present invention can include resins
other than the polyester resin (R), a photoinitiator, or other
additives. Examples of resins other than the polyester resin (R)
include an acrylic resin, a urethane resin, an epoxy resin, and a
polycarbonate. These other resins can be used usually at 100 parts
by weight or less and preferably at 50 parts by weight or less on
the basis of 100 parts by weight of the polyester resin (R).
[0040] Also, examples of the photoinitiator include
1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one,
1-hydroxy-cyclohexyl-phenyl-ketone,
2,2-dimethoxy-1,2-diphenylethan-1-one,
2,4,6-trimethylbenzoyldiphenylphosphine oxide,
2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone-1,2-hydroxy-2-met-
hyl-1-phenyl-propan-1-one,
2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, benzoin
ethyl ether, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide,
isopropyl thioxanthone, methyl o-benzoylbenzoate,
[4-(methylphenylthio)phenyl]phenyl methanone, benzophenone, and
p-dimethylaminobenzoic acid isoamylethyl ester.
[0041] Among them, preferable examples of the photoinitiator
include
1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one,
1-hydroxy-cyclohexyl-phenyl-ketone,
2,2-dimethoxy-1,2-diphenylethan-1-one,
2,4,6-trimethylbenzoyldiphenylphosphine oxide,
2-hydroxy-2-methyl-1-phenyl-propan-1-one, and
bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide.
[0042] The photoinitiator can be used usually at 10 parts by weight
or less and preferably at 0.1 to 6 parts by weight on the basis of
100 parts by weight of the sum of the polyester resin (R) and the
polymerizable vinyl compound (V) (or the resin component which is
curable with irradiation).
[0043] Furthermore, examples of the other additives include a
mold-releasing agent which improves a mold-releasing property in a
mold-releasing step, a colorant such as a pigment or a dye, an
antioxidant, a photodispersing agent, and a thermal polymerization
inhibitor.
[0044] Among these other additives, it is preferable to blend a
thermal polymerization inhibitor for the purpose of maintaining
thermal polymerization inhibition and storage stability during the
production of a radiation-curable resin composition for
shape-replication of the present invention. There is no particular
limitation to the thermal polymerization inhibitor, and
representative examples thereof include hydroquinone, hydroquinone
monomethyl ether, tert-butylcatechol, p-benzoquinone, and
phenothiazine. The thermal polymerization inhibitor is used usually
at 2 parts by weight or less and preferably at 0.05 to 1 parts by
weight on the basis of 100 parts by weight of the sum of the
polyester resin (R) and the polymerizable vinyl compound (V) (or
the resin component which is cured by heating).
[0045] There are various methods to be used for the production of a
shape-replicated material by using a radiation-curable resin
composition for shape-replication of the present invention.
Examples of the production method are as follows.
[0046] Method 1 includes heating each of a sheet for
shape-replication obtained by the method described below and a flat
or roll-shape-replicated mold on which a shape-replicating pattern
is formed; touching the sheet for shape-replication to the mold
such that the radiation-curable resin composition for
shape-replication layer of the sheet for shape-replication is on
the side of the mold, followed by shape-replicating by
pressurizing; and then curing the radiation-curable resin
composition with irradiation followed by mold-releasing.
[0047] Method 2 includes heating each of a shape-replicated sheet
obtained by the method described below and a flat or
roll-shape-replicated mold on which a shape-replicating pattern is
formed; touching the shape-replicated sheet to the mold such that
the radiation-curable resin composition for shape-replication layer
of the shape-replicated sheet is on the side of the mold, followed
by shape-replicating by heating and mold-releasing; and then curing
the radiation-curable resin composition on exposure to
radiation.
[0048] In method 2, it is possible to improve a mold-releasing
property by cooling after shape-replicating with pressing, which
follows touching the shape-replicated sheet to the mold.
[0049] Herein, a radiation-curable resin composition for
shape-replication of the present invention can include a
mold-releasing agent. Due to a mold-releasing agent included in the
composition, a mold-releasing property can be improved without
cooling after shape-replicating with pressing which follows
touching the shape-replicated sheet to the mold in method 2.
[0050] Examples of the mold-releasing agent include solid waxes
such as polyethylene wax, amide wax, Teflon (registered trademark)
powder; a fluorine-based or phosphate-based surfactant; a
fluorine-containing resin; and a silicone compound. Among them, a
silicone compound is preferable.
[0051] Preferable examples of the silicone compound include a
polyether-modified and/or polyester-modified silicone compounds
such as a polyether-modified silicone compound, a
polyester-modified silicone compound, or a polyether-modified and
polyester-modified silicone compound.
[0052] Examples of the polyether-modified and/or polyester-modified
silicone compounds include a compound in which a polyether chain
and/or a polyester chain are introduced at ends and/or side chains
of polysiloxane, and also includes a co-modified silicon compound
in which an organic group other than polyethers and polyesters,
such as an epoxy group or an amino group, is introduced together
into polysiloxane. Also, it is preferable for the
polyether-modified and/or polyether-modified silicone compounds to
include a (meth)acryloyl group in a molecule because a sufficient
crosslink density can be obtained after curing on exposure to
radiation.
[0053] Examples of the polyether-modified silicone compound include
KF-351, KF-352, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-618,
KF-6011, KF-6015, KF-6004, X-2-4272, X-2-4952, X-2-6266, X-2-3667,
X-2-4741, X-2-3939A, X-2-3908A (these are produced by Shin-Etsu
Chemical Co., Ltd.); BYK-300, BYK-302, BYK-306, BYK-310, BYK-320,
BYK-325, BYK-330, BYK-331, BYK-333, BYK-337, BYK-344, BYK-375,
BYK-377, BYK-UV3510, BYK-301, BYK-307, BYK-325, BYK-341, BYK-345,
BYK-346, BYK-347, BYK-348 (these are produced by BYK Chemie Co.,
Ltd.); SILWET L-77, SILWET L-720, SILWET L-7001, SILWET L-7002,
SILWET L-7604, SILWET Y-7006, SILWET FZ-2101, SILWET FZ-2104,
FZ-2105, SILWET FZ-2110, SILWET FZ-2118, SILWET FZ-2120, SILWET
FZ-2122, SILWET FZ-2123, SILWET FZ-2130, SILWET FZ-2154, SILWET
FZ-2161, SILWET FZ-2162, SILWET FZ-2163, SILWET FZ-2164, SILWET
FZ-2166, SILWET FZ-2191, SILWET FZ-2203, SILWET FZ-2207, SILWET
2208, SILWET FZ-3736, SILWET Y-7499, SILWET FZ-3789, SF8472,
BY16-004, SF8428, SH3771, SH3746, BY16-036, SH3749, SH3748, SH8400,
SF8410 (these are produced by Toray Dow Corning Silicone Co.,
Ltd.); and L032, L051, L066 (these are produced by Asahi Chemical
Industry Wacker silicone Co., Ltd.). Also, examples of this
compound including at least one (meth)acryloyl group in a molecule
include BYK-UV3500, BYK-UV3570, BYK-UV3530 (these are produced by
BYK Chemie Co., Ltd.).
[0054] Also, examples of the polyester-modified silicone compound
include BYK-310, BYK-315, BYK-370 (these are produced by BYK Chemie
Co., Ltd.). Also, examples of this compound including at least one
(meth)acryloyl group in a molecule include BYK-UV3570 (these are
produced by BYK Chemie Co., Ltd.). These polyether-modified or
polyester-modified silicone compounds can be used alone or in a
combination of two or more.
[0055] The polyether-modified or polyester-modified silicone
compound is used within the content range in which transparency
preferable for the use in optical articles and the solubility of a
radiation-curable resin composition can be maintained. As for the
content thereof, the content range in the nonvolatile components of
a radiation-curable resin composition is preferably 1 to 15 wt %
and more preferably 3 to 10 wt %. This content level is high in
comparison with the case of a mold-releasing agent such as a
silicone-based compound used in a general cast polymerization. In
the case of a radiation-curable resin composition in which a
mold-releasing agent is blended so as to increase viscosity of the
produced composition such that a shape-replicating property is
maintained and that a resin layer is not flowed before or after
shape-replicating, a bleed property (the property in which the
low-molecular-weight components of a resin ooze out on surface.)
becomes poor in comparison with the case of a general cast
polymerization. Therefore, the polyether-modified or
polyester-modified silicone compound needs to be used in a large
amount so as to exert a mold-releasing property under the condition
of such a poor bleed property.
[0056] In the present invention, a sheet for shape-replication
means the article in which the aforementioned radiation-curable
resin composition for shape-replication is laminated on one side or
both sides of a sheet-type resin substrate. There is no particular
limitation to the sheet-type resin substrate used in the sheet for
shape-replication, and preferable examples thereof include a
sheet-type resin substrate made of a polyester-based resin
represented by poly(ethylene terephthalate), a sheet-type resin
substrate made of an acrylic resin represented by poly(methyl
methacrylate), and a sheet-type resin substrate made of a
polycarbonate resin. According to these preferable examples, it is
possible to cure a resin layer by irradiation through either side
of a sheet when a resin layer, which is obtained by laminating and
shape-replicating a radiation-curable resin composition on one side
or both sides of these substrates, is irradiated. There is no
particular limitation to the thickness of a sheet-type resin
substrate, and the thickness can be determined according to
purpose. The thickness of a sheet-type resin substrate is
preferably 38 to 500 .mu.m, and more preferably 50 to 250 .mu.m.
Also, the surface of a sheet-type resin substrate is preferably
subjected to an adhesiveness-improving treatment such as a corona
discharge treatment, a plasma treatment, or a primer treatment for
the purpose of improving adhesiveness between a sheet-type resin
substrate and a resin layer.
[0057] There is no particular limitation to the thickness of the
layer of a radiation-curable resin composition for
shape-replication excluding any solvent laminated on one side or
both sides of a sheet-type resin substrate, and the thickness can
be determined according to purpose. The thickness of a resin layer
is usually 10 .mu.m to 1 mm, and preferably 50 to 500 .mu.m, and is
preferably 1 to 5 times as much as a maximum depth of a mold.
[0058] There is no particular limitation to a method of laminating
a radiation-curable resin composition for shape-replication on one
side or both sides of a sheet-type resin substrate, and examples
thereof include the method including dissolving a radiation-curable
resin composition in a solvent such as a toluene, xylene, ethyl
acetate, butyl acetate, acetone, methyl ethyl ketone, methyl
isobutyl ketone, ethanol, isopropanol according to need so as to
prepare a uniform solution; flow-casting this solution on a
sheet-type resin substrate by using various coaters; and then
removing a solvent by evaporation with a drying oven. Also,
examples thereof include the method including heating a uniformly
mixed radiation-curable resin composition so as to decrease
viscosity followed by applying the composition on a sheet-type
resin substrate; and solidifying it by cooling. Among them, the
latter method is more preferable because it is difficult to
completely remove a solvent especially during a thick film-coating
step. Herein, in the case of preparing a solution using a solvent,
resin components are dissolved preferably at 40 wt % or more, and
more preferably at 50 wt % or more in the equivalent of the
film-forming components.
[0059] A shape-replicated material can be produced by
shape-replicating a sheet for shape-replication of the present
invention and then curing it on exposure to radiation.
Shape-replicating of a sheet for shape-replication is performed by
shape-replicating a layer of a radiation-curable resin composition
for shape-replication laminated on one side or both sides of a
sheet-type resin substrate. Examples thereof include the method
including heating a sheet for shape-replication of the present
invention up to the temperature at which a complex viscosity
(.eta.*) of a radiation-curable resin composition for
shape-replication excluding any solvent at a frequency of 1 Hz is
1.times.10.sup.4 to 1.times.10.sup.6 dPas, preferably the
temperature at which a complex viscosity (.eta.*) at a frequency of
1 Hz is about 1.times.10.sup.5 dPas such as 0.63.times.10.sup.5 to
1.58.times.10.sup.5 dPas; bringing the sheet for shape-replication
into contact with a flat shape-replicating mold followed by
shape-replicating with pressing; and then curing it on exposure to
radiation followed by mold-releasing so as to obtain a
shape-replicated material such as an optical lens sheet. Also,
examples thereof include the method including heating a sheet for
shape-replication in the same way as the aforementioned; performing
shape-replicating and mold-releasing by continuous pressing using a
roll-shape-replicated shape-replicating mold as described in the
aforementioned "JP '503" and other reference (for example, see
Japanese Unexamined Patent Application, First Publication No. Hei
1-159627); and then curing it on exposure to radiation so as to
obtain a shape-replicated material such as an optical lens
sheet.
[0060] Herein, examples of a light source of radiation used for
curing include various sources such as a low-pressure or
high-pressure mercury-vapor lamp, a metal halide lamp, a xenon
lamp, an electrodeless discharge lamp, and a carbon-arc lamp.
EXAMPLES
[0061] The present invention will now be described in detail by way
of Examples and Comparative Examples, but the present invention is
not limited thereto. In Examples, parts are by mass unless
otherwise described.
Example 1
[0062] 812 parts of bisphenol A-propylene oxide adducts (BAP2
glycol produced by Nippon Nyukazai Co., Ltd.) and 272 parts of
fumaric acid were reacted in the presence of 1.1 parts of dibutyl
tin oxide at 215.degree. C. for 8 hours, thereby obtaining a
polyester resin (R1) which has unsaturated double bonds in a
molecule, a number average molecular weight (Mn) of 2,300, and a
softening point of 100.degree. C.
[0063] Herein, a number average molecular weight (Mn) of a
polyester resin is a polystyrene equivalent number average
molecular weight obtained by the measurement at a flow rate of
0.350 ml/min using a high speed gel permeation chromatography
apparatus produced by Tosoh Corporation (HLC-8220GPC) and columns
produced by Tosoh Corporation (each one of TSKgel SuperHZ4000,
SuperHZ3000, SuperHZ2000, and SuperHZ1000), and tetrahydrofuran as
a solvent (hereinafter, the same is applied).
[0064] Subsequently, in a separable flask, 65 parts of the obtained
polyester resin (R1), 28 parts of urethane acrylate oligomer
(UNIDIC V-4260 produced by Dainippon Ink and Chemicals, Inc.,
number average molecular weight: 1,700, the number of an average
unsaturated group: 3), 3 parts of the product of the reaction of
dipentaerythritol and acrylic acid (KAYARAD DPHA produced by Nippon
Kayaku Co., Ltd., the mixture of dipentaerythritol hexaacrylate
(the number of functional group: 6) and dipentaerythritol
pentaacrylate (the number of functional group: 5)), and 4 parts of
2,2-dimethoxy-1,2-diphenylethan-1-one (IRGACURE 651 produced by
Ciba Specialty Chemicals K.K.) were dissolved in 50 parts of ethyl
acetate, and then defoamed by depressurizing, thereby obtaining a
uniform radiation-curable resin composition for shape-replication.
The temperature (T6), at which a complex viscosity (.eta.*) of the
obtained radiation-curable resin composition for shape-replication
at a frequency of 1 Hz is 1.times.10.sup.6 dPas, is 37.degree. C.,
the temperature (T5), at which a complex viscosity (.eta.*) at a
frequency of 1 Hz is 1.times.10.sup.5 dPas, was 55.degree. C., and
the temperature (T4), at which a complex viscosity (.eta.*) of the
components excluding any solvent at a frequency of 1 Hz is
1.times.10.sup.4 dPas, was 72.degree. C. Also, the temperature
difference (T4-T6) was 35.degree. C.
[0065] On one side of the poly(ethylene terephthalate) film (TOYOBO
ester.RTM. film A4300 produced by TOYOBO Co., Ltd.) with a
thickness of 100 .mu.m, the obtained radiation-curable resin
composition for shape-replication was applied and dried 3 times by
using an applicator, thereby obtaining a sheet for
shape-replication (S1) in which the layer of the radiation-curable
resin composition for shape-replication with a thickness of 100
.mu.m was laminated on one side of the sheet-type resin
substrate.
[0066] Each of the obtained sheet for shape-replication (S1) and a
flat mold, in which rectangular grooves with a bottom width of 93
.mu.m, a top width of 103 .mu.m, and a depth of 40 .mu.m were
parallel formed at a spacing of 47 .mu.m, was heated up to
55.degree. C., and the sheet for shape-replication was brought into
contact with the mold such that the layer of the radiation-curable
resin composition for shape-replication was on the side of the
mold, and then the sheet for shape-replication was shape-replicated
with pressing at a pressure of 98 kPa for 2 seconds. Subsequently,
the sheet was separated from the mold after cooling down to
40.degree. C., and irradiated by ultraviolet rays with 1000
mJ/cm.sup.2 from a UV lamp, thereby obtaining the shape-replicated
sheet (Sc1), in which the pattern of the mold was replicated to the
radiation-curable resin composition.
[0067] The obtained shape-replicated sheet (Sc1) was not damaged
during mold-releasing and other treatments and was excellent in a
mechanical property. When this shape was measured by using a laser
microscope (the ultradeep shape-measuring microscope VK-8510
produced by Keyence Corporation), the flat part width at the top
part of rectangular shape corresponding to the bottom part (width:
93 .mu.m) of the rectangular groove was 90 .mu.m or more, and it
was confirmed that the shape of the mold was precisely
replicated.
Example 2
[0068] To a separable flask, 37 parts of the polyester resin (R1)
obtained in Example 1, 56 parts of epoxy acrylate oligomer (UNIDIC
V-5500 produced by Dainippon Ink and Chemicals, Incorporated,
number average molecular weight: 520, the number of an average
unsaturated group: 2), 3 parts of KAYARAD DPHA, and 4 parts of
IRGACURE 651 were added, stirred and heated at 100.degree. C., and
then defoamed by depressurizing, thereby obtaining a uniform
radiation-curable resin composition for shape-replication. The
temperature (T6), at which a complex viscosity (.eta.*) of the
obtained radiation-curable resin composition for shape-replication
at a frequency of 1 Hz is 1.times.10.sup.6 dPas, is 32.degree. C.,
the temperature (T5), at which a complex viscosity (.eta.*) at a
frequency of 1 Hz is 1.times.10.sup.5 dPas, was 44.degree. C., and
the temperature (T4), at which a complex viscosity (.eta.*) of the
components excluding any solvent at a frequency of 1 Hz is
1.times.10.sup.4 dPas, was 60.degree. C. Also, the temperature
difference (T4-T6) was 28.degree. C.
[0069] The obtained radiation-curable resin composition for
shape-replication, the poly(ethylene terephthalate) film A4300, and
an applicator were previously heated up to 95.degree. C. Then, on
the hotplate whose temperature was controlled to be 95.degree. C.,
the radiation-curable resin composition for shape-replication was
applied on one side of the poly(ethylene terephthalate) film A4300
by using an applicator, thereby obtaining a sheet for
shape-replication (S2) in which the layer of the radiation-curable
resin composition for shape-replication with a thickness of 100
.mu.m was laminated on one side of the sheet-type resin
substrate.
[0070] Each of the obtained sheet for shape-replication (S2) and a
flat mold, in which rectangular grooves with a bottom width of 93
.mu.m, a top width of 103 .mu.m, and a depth of 40 .mu.m were
parallel formed at a spacing of 47 .mu.m, was heated up to
45.degree. C., the sheet for shape-replication was brought into
contact with the mold such that the layer of the radiation-curable
resin composition for shape-replication was on the side of the
mold, and then the sheet for shape-replication was shape-replicated
with pressing at a pressure of 98 kPa for 2 seconds. Subsequently,
the sheet was separated from the mold after cooling down to
30.degree. C., and the pattern of the mold was replicated to the
radiation-curable resin composition on exposure to ultraviolet rays
with 1000 mJ/cm.sup.2 from a UV lamp, thereby obtaining a
shape-replicated sheet (Sc2).
[0071] The obtained shape-replicated sheet (Sc2) was not damaged
during mold-releasing and other treatments and was excellent in a
mechanical property. When the shape was measured by using a laser
microscope, the flat part width at the top part of rectangular
shape corresponding to the bottom part (width: 93 .mu.m) of the
rectangular groove was 90 .mu.m or more, and it was confirmed that
the shape of the mold was precisely replicated.
Example 3
[0072] To a separable flask, 74 parts of the polyester resin (R1)
obtained in Example 1, 19 parts of UNIDIC V-4260, 3 parts of
KAYARAD DPHA, 4 parts of IRGACURE 651, and 4 parts of
polyether-modified polydimethylsiloxane (SILWET FZ-2164 produced by
Toray Dow Corning Silicone Co., Ltd.) were added, stirred and
heated at 110.degree. C., and then defoamed by depressurizing,
thereby obtaining a uniform radiation-curable resin composition for
shape-replication. The temperature (T6), at which a complex
viscosity (.eta.*) of the obtained radiation-curable resin
composition for shape-replication at a frequency of 1 Hz is
1.times.10.sup.6 dPas, is 42.degree. C., the temperature (T5), at
which a complex viscosity (.eta.*) at a frequency of 1 Hz is
1.times.10.sup.5 dPas, was 58.degree. C., and the temperature (T4),
at which a complex viscosity (.eta.*) of the components excluding
any solvent at a frequency of 1 Hz is 1.times.10.sup.4 dPas, was
74.degree. C. Also, the temperature difference (T4-T6) was
32.degree. C.
[0073] The obtained radiation-curable resin composition for
shape-replication, the poly(ethylene terephthalate) film A4300, and
an applicator were previously heated up to 95.degree. C. Then, on
the hotplate whose temperature was controlled to be 95.degree. C.,
the radiation-curable resin composition for shape-replication was
applied on one side of the poly(ethylene terephthalate) film A4300
by using an applicator, thereby obtaining a sheet for
shape-replication (S3) in which the layer of the radiation-curable
resin composition for shape-replication with a thickness of 200
.mu.m was laminated on one side of the sheet-type resin
substrate.
[0074] The obtained sheet for shape-replication (S3) was heated up
to 55.degree. C., and passed between a pressurizing roll and a
roll-shape-replicated mold, on which grooves of a cylindrical lens
pattern with a depth of 70 .mu.m and a pitch of 145 .mu.m were
formed, so as to shape-replicate with pressing. Then, the sheet was
irradiated by ultraviolet rays with 1000 mJ/cm.sup.2 from a UV
lamp, thereby obtaining the shape-replicated sheet (Sc3), in which
the pattern of the mold was replicated to the layer of the
radiation-curable resin composition for shape-replication.
[0075] The obtained shape-replicated sheet (Sc3) was not damaged
during mold-releasing and other treatments and was excellent in a
mechanical property. When the shape was measured by using a laser
microscope, it was confirmed that the cylindrical lens pattern with
a height of 63 .mu.m corresponding to the depth of the cylindrical
lens pattern was precisely replicated. Herein, the obtained
shape-replicated sheet (Sc3) is highly transparent and excellent in
adhesiveness between the cured layer of the radiation-curable resin
composition for shape-replication and a poly(ethylene
terephthalate) film.
Example 4
[0076] To a separable flask, 42 parts of the polyester resin (R1)
obtained in Example 1, 51 parts of UNIDIC V-4260, 3 parts of
KAYARAD DPHA, 4 parts of IRGACURE 651, and 4 parts of
polyether-modified polydimethylsiloxane (SILWET FZ-2164 produced by
Toray Dow Corning Silicone Co., Ltd.) were added, stirred and
heated at 110.degree. C., and then defoamed by depressurizing,
thereby obtaining a uniform radiation-curable resin composition for
shape-replication. The temperature (T6), at which a complex
viscosity (.eta.*) of the obtained radiation-curable resin
composition for shape-replication at a frequency of 1 Hz is
1.times.10.sup.6 dPas, is 9.degree. C., the temperature (T5), at
which a complex viscosity (.eta.*) at a frequency of 1 Hz is
1.times.10.sup.5 dPas, was 21.degree. C., and the temperature (T4),
at which a complex viscosity (.eta.*) of the components excluding
any solvent at a frequency of 1 Hz is 1.times.10.sup.4 dPas, was
32.degree. C. Also, the temperature difference (T4-T6) was
23.degree. C.
[0077] A sheet for shape-replication (S4) was produced in the same
manner as in Example 1 except for using the obtained
radiation-curable resin composition for shape-replication. The
obtained sheet for shape-replication (S4) was brought into contact
with a flat mold in which rectangular grooves with a bottom width
of 93 .mu.m, a top width of 103 .mu.m, and a depth of 40 .mu.m were
parallel formed at a spacing of 47 .mu.m, and then the sheet for
shape-replication was shape-replicated by pressurizing at a
pressure of 98 kPa for 2 seconds. Subsequently, the sheet was
separated from the mold, and the pattern of the mold was replicated
to the radiation-curable resin composition on exposure to
ultraviolet rays with 1000 mJ/cm.sup.2 from a UV lamp, thereby
obtaining a shape-replicated sheet (Sc4).
[0078] In the obtained shape-replicated sheet (Sc4), the resin
layer became nonuniform due to the pressure during replicating the
mold, and therefore, a shape-replicated shape was slightly
nonuniform. However, the obtained shape-replicated sheet (Sc4) was
not damaged during mold-releasing and other treatments and was
excellent in a mechanical property. When this shape was measured by
using a laser microscope, the average flat part width at the top
part of rectangular shape corresponding to the bottom part (width:
93 .mu.m) of the rectangular groove was 90 .mu.m or more, and it
was confirmed that the shape of the mold was precisely
replicated.
Example 5
[0079] 224 g of the propylene glycol, 432 g of cyclohexane
dimethanol, 33 g of EPICLON 830 (bisphenol F type epoxy resin
produced by Dainippon Ink and Chemicals, Inc.), 45 g of CARDURA E10
(product of Shell Japan Ltd., neodecanoic acid glycidyl ester), 996
g of isophthalic acid, and 1.0 g of dibutyl tin oxide were mixed,
gradually heated in a nitrogen flow, and then reacted at
245.degree. C., for 18 hours, thereby obtaining a polyester resin
(R2) with a number average molecular weight (Mn) of 6,200 and a
softening point of 186.degree. C.
[0080] In a separable flask, 85 parts of the obtained polyester
resin (R2), 8 parts of UNIDIC V-5500, 3 parts of KAYARAD DPHA, and
4 parts of IRGACURE 651 were dissolved in 100 parts of ethyl
acetate, and then defoamed by depressurizing, thereby obtaining a
uniform radiation-curable resin composition for shape-replication.
The temperature (T6), at which a complex viscosity (.eta.*) of the
obtained radiation-curable resin composition for shape-replication
at a frequency of 1 Hz is 1.times.10.sup.6 dPas, is 95.degree. C.,
the temperature (T5), at which a complex viscosity (.eta.*) at a
frequency of 1 Hz is 1.times.10.sup.5 dPas, was 113.degree. C., and
the temperature (T4), at which a complex viscosity (.eta.*) of the
components excluding any solvent at a frequency of 1 Hz is
1.times.10.sup.4 dPas, was 133.degree. C. Also, the temperature
difference (T4-T6) was 38.degree. C.
[0081] A sheet for shape-replication (S5) was produced in the same
manner as in Example 1 except for using the obtained
radiation-curable resin composition for shape-replication. A
shape-replicated sheet (Sc5) was produced by shape-replicating and
irradiating ultraviolet rays in the same manner as in Example 1
except for using the obtained sheet for shape-replication (S5). The
obtained shape-replicated sheet (Sc5) was not damaged during
mold-releasing and other treatments and was excellent in a
mechanical property. When this shape was measured by using a laser
microscope, the flat part width at the top part of rectangular
shape corresponding to the bottom part (width: 93 .mu.m) of the
rectangular groove was 80 .mu.m or more, and it was confirmed that
the shape of the mold was precisely replicated.
Comparative Example 1
[0082] In a separable flask, 65 parts of an acrylic resin (FINEDIC
A-251 produced by Dainippon Ink and Chemicals, Inc., a number
average molecular weight (Mn): 7,300), 28 parts of urethane
acrylate oligomer (UNIDIC V-4260 produced by Dainippon Ink and
Chemicals, Inc), 3 parts of KAYARAD DPHA, and 4 parts of IRGACURE
651 were dissolved in 50 parts of ethyl acetate, and then defoamed
by depressurizing, thereby obtaining a uniform radiation-curable
resin composition for comparison. The temperature (T6), at which a
complex viscosity (.eta.*) of the obtained radiation-curable resin
composition for shape-replication at a frequency of 1 Hz was
1.times.10.sup.6 dPas, is 52.degree. C., the temperature (T5), at
which a complex viscosity (.eta.*) at a frequency of 1 Hz is
1.times.10.sup.5 dPas, was 70.degree. C., and the temperature (T4),
at which a complex viscosity (.eta.*) of the components excluding
any solvent at a frequency of 1 Hz is 1.times.10.sup.4 dPas, was
85.degree. C. Also, the temperature difference (T4-T6) was
33.degree. C.
[0083] A sheet for shape-replication (S1') was produced in the same
manner as in Example 1 except for using the obtained
radiation-curable resin composition for comparison.
[0084] A shape-replicated sheet (Sc1') was produced by
shape-replicating and irradiating ultraviolet rays in the same
manner as in Example 1 except for using the obtained sheet for
shape-replication (S1') and heating each of the sheet for
shape-replication and the mold before shape-replicating.
[0085] The cured resin layer of the obtained shape-replicated sheet
(Sc1') was very brittle, and it was peeled from the sheet-type
resin substrate made of poly(ethylene terephthalate) after
mold-releasing, and broken immediately.
Comparative Example 2
[0086] In a separable flask of 2 L, 65 parts of U-polymer (a
polyarylate resin produced by Unitika Ltd., a number average
molecular weight (Mn): 16,000), 3 parts of UNIDIC V-4260, 3 parts
of KAYARAD DPHA, and 4 parts of IRGACURE 651 were dissolved in 400
parts of ethyl acetate, and dissolved under reflux. However, these
were not dissolved uniformly so as not to be able to produce a
radiation-curable resin composition for shape-replication.
Therefore, further treatment for producing a sheet for
shape-replication was abandoned.
Comparative Example 3
[0087] The radiation-curable resin composition for
shape-replication was obtained in the same manner as in Example 1
except for using 37 parts of the obtained polyester resin (R1) and
56 parts of UNIDIC V-4260. The temperature (T6), at which a complex
viscosity (.eta.*) of the obtained radiation-curable resin
composition for shape-replication at a frequency of 1 Hz is
1.times.10.sup.6 dPas, was 3.degree. C., the temperature (T5), at
which a complex viscosity (.eta.*) at a frequency of 1 Hz is
1.times.10.sup.5 dPas, was 14.degree. C., and the temperature (T4),
at which a complex viscosity (.eta.*) of the components excluding
any solvent at a frequency of 1 Hz is 1.times.10.sup.4 dPas, was
26.degree. C. Also, the temperature difference (T4-T6) was
23.degree. C.
[0088] A sheet for shape-replication (S3') was produced in the same
manner as in Example 1 except for using the obtained
radiation-curable resin composition for shape-replication. An
obtained sheet for shape-replication (S3') was brought into contact
with a flat mold in which rectangular grooves with a bottom width
of 93 .mu.m, a top width of 103 .mu.m, and a depth of 40 .mu.m were
parallel formed at a spacing of 47 .mu.m, and then the sheet for
shape-replication was shape-replicated with pressing at a pressure
of 98 kPa for 2 seconds. Subsequently, the sheet was separated from
the mold, and the pattern of the mold was replicated to the
radiation-curable resin composition on exposure to ultraviolet rays
with 1000 mJ/cm.sup.2 from a UV lamp, thereby obtaining the
shape-replicated sheet (Sc3').
[0089] In the obtained shape-replicated sheet (Sc3'), the resin
layer of the sheet for shape-replication partially flowed out from
the sheet-type resin substrate, and the sheet-type resin substrate
and the mold were touched. Therefore, a shape-replicated material
with a favorable shape-replicating pattern could not be
obtained.
Comparative Example 4
[0090] In a separable flask, 93 parts of an polyester resin (R2), 3
parts of KAYARAD DPHA, and 4 parts of IRGACURE 651 were dissolved
in 50 parts of ethyl acetate, and then defoamed by depressurizing,
thereby obtaining the uniform radiation-curable resin composition
for comparison. The temperature (T6), at which a complex viscosity
(.eta.*) of the obtained radiation-curable resin composition for
shape-replication at a frequency of 1 Hz is 1.times.10.sup.6 dPas,
was 110.degree. C. The temperature (T5), at which a complex
viscosity (.eta.*) at a frequency of 1 Hz is 1.times.10.sup.5 dPas,
and the temperature (T4), at which a complex viscosity (.eta.*) of
the components excluding any solvent at a frequency of 1 Hz is
1.times.10.sup.4 dPas, could not be measured because the resin
composition was gelated during the measurement.
[0091] On one side of a poly(ethylene terephthalate) film with a
thickness of 100 .mu.m, the obtained radiation-curable resin
composition for shape-replication was applied and dried 3 times by
using an applicator, thereby obtaining a sheet for
shape-replication (S4') in which the radiation-curable resin
composition for shape-replication layer with a thickness of 100
.mu.m was laminated on one side of the sheet-type resin
substrate.
[0092] Each of the obtained sheet for shape-replication (S4') and a
flat mold, in which rectangular grooves with a bottom width of 93
.mu.m, a top width of 103 .mu.m, and a depth of 40 .mu.m were
parallel formed at a spacing of 47 .mu.m, was heated up to
120.degree. C. (this is the limit temperature at which the used
poly(ethylene terephthalate) film was not thermally deformed, and
the sheet for shape-replication was brought into contact with the
mold such that the layer of the radiation-curable resin composition
for shape-replication was on the side of the mold, and then the
sheet for shape-replication was shape-replicated by pressurizing at
a pressure of 98 kPa for 2 seconds. Subsequently, the sheet was
separated from the mold after cooling down to 40.degree. C., and
the pattern of the mold was replicated to the radiation-curable
resin composition on exposure to ultraviolet rays with 1000
mJ/cm.sup.2 from a UV lamp, thereby obtaining the shape-replicated
sheet (Sc4').
[0093] The obtained shape-replicated sheet (Sc4') had an ambiguous
shape, and was useless from a practical viewpoint.
[0094] A radiation-curable resin composition for shape-replication
of the present invention is excellent in a mechanical property of a
cured material. In addition, there is the case where it is possible
to flow-cast the composition on a sheet-type resin substrate by
appropriately heating it without any solvent. In the case of
preparing a solution using a solvent, it is possible to dissolve
the composition without using a solvent with strong solubility.
Also, since the solution requires a small amount of solvent, foams
hardly occur in the case of removing the solvent by evaporation
after the solution has been flow-cast on a sheet-shape-replicated
resin material. In addition, it is easy to improve a
shape-replicating property by heating, and the balance of a
shape-replicating property and a mechanical property of a cured
material is favorable. Also, it is easy to obtain a cured material
which is excellent in a mechanical property and on which a shape of
a mold such as a lens pattern is precisely replicated. Accordingly,
the present invention is industrially useful.
* * * * *